The present invention relates to the field of systems for the thermal regulation of engines and, more specifically, to the field of systems for regulating the distribution of the liquid coolant in an engine.
By regulating the temperature of the combustion engine it becomes possible to conceive of reducing the emissions of pollutants of the fuel consumption of the engine as the engine warms up. During the transient phase, as the combustion engine warms up, it is found to consume excessive amounts of fuel as a result of the high viscosity of the engine lubricating oil and as a result of a phenomenon of incomplete combustion with significant emissions of hydrocarbons and monoxides, notably of carbon and of nitrogen, because of the low combustion chamber wall temperature.
In order to reduce the consumption and pollutant emissions as the combustion engine warms up, the engine is not cooled. The metallic masses and the lubricating oil have temperatures which increase more rapidly than they would if liquid coolant was circulated through the engine. The flow rate of liquid coolant through the engine is therefore shut off during the warming-up phase.
At the same time, in order to restrict the amount of emissions of monoxides, for example of nitrogen, the exhaust gases are fed back from the exhaust to the intake side of the combustion engine, causing them to undergo a cooling step, using an E.G.R (exhaust gas recirculation) system. Likewise, in order to cool the turbocompressor bearing, it is appropriate to use a cooled casing in which the liquid coolant circulates so as to pick up heat from the metallic mass and from the oil of the turbocompressor.
These various thermal regulations of the engine, on the one hand, and of the consumers that are the turbocompressor and the E.G.R device that recirculates the gases, on the other hand, need to be performed at the same time. Specifically, during the warm-up phase, it is important for the turbocompressor and the exhaust gas recirculation device always to be cooled.
At the present time, thermal regulation involves a wax thermostat incorporated into the combustion engine cooling circuit. It is important that the new regulations be carried out with a limited additional cost over the existing regulating systems.
Various devices have been proposed in an attempt to address the problems of the various forms of thermal regulation with the circulation of liquid coolant when carrying out thermal regulation on an engine.
One known system for regulating the circulation of liquid coolant involves positioning a three-way valve on the inlet side of the engine, downstream of the water pump, this three-way valve supplying a pipe that allows the liquid coolant to circulate between the water pump downstream of the engine and an engine outlet which supplies the consumers. However, such a system has the disadvantage of being unable to conform to the fitting requirements especially since fitting a valve between the water pump and the crankcase upper half of the engine remains a complicated task.
An alternative form of this system for regulating the circulation of liquid coolant is to position the three-way valve on the outlet side of the engine, this valve supplying the pipe with short-circuits the circulation of liquid coolant through the engine. However, this solution does not address the problem of fitting a tapping between the water pump and the crankcase upper half of the engine.